Device for governing the engine speed of a multicylinder injection internal combustion engine



DEVICE FOR GOVERNING THE ENGINE SPEED OF A MULTICYLINDER Feb. 25, 1941.SCHWElZER 2,233,036

v INJECTION INTERNAL COMBUSTION ENGINE Filed June 3, 1958- y Q ////////lPatented Feb. 25, 1941" '1 -9 DEVICE ron' oovaaume rim ,nmnm sPEEn'or Am'ncrmmsa mmcrron mama comnusrron ENGINE 1 Alfred Schweizer,Vaihingen-on-the-Filders, Ger.

many, assignor to Robert Bosch Gcsellschaft mit beschriinkter Haftung,Stuttgart, Germany Application June 3, 1938, Serial No. 211,682 I InGermany June 17,1937

The present invention relates to devices for governing the enginespeedof multicylinder injection internal combustion engines with the aidof a control member, which displaces the member 5 of the injection pump,adjusting the fuel delivery amount and which divides the governor casinginto two chambers and is moved against a return force by agoverningforce produced against a constant pneumatic pressure,especially atmospheric pressure, by an air pressure drop, which forcevaries with the engine speed and can be influenced by the voluntaryadjustment of a throttle member. 1

If, in governors of this kind, one force which helps to determine theair pressure drop is formed by atmospheric pressure, and if theatmosphere has direct free admission to the governor chamber situated onone side of the control member, then foreign bodies, especially dust,which hinder A 34 the free mobility of the control member, can

easily get into this chamber. It has been proved that, owing to its toand fro movements, which are often rapid on a rapid change of enginespeed, the control member also sucks dust into the con- 25 trol chambertogether with the air, and the dust then settles on the walls of thegovernor or on' the control member itself. If the control member has apiston which is guided in the governor casing so as to be airtight,this'piston can be 30 hindered in motion by the dust, especially whenthe engine has been stationary for some time. If the control memberconsists of an oil impregnated leather diaphragm, the diaphragm losesits resilience owing to the dirt which settles on it, 35 and becomeseasily broken and leaky.-

Now the external air could be cleaned by a filter before entering thegovernor chamber. Since, however, free passage through the filtergradually becomes constricted owing to the impurities, the 40 externalair pressure can no longer be transmitted without hindrance to theinterior of the chamber, so that the governor no longer responds quicklyto pressure difference.

In order to avoid the drawbacks set forth, ac- 4 cording to the presentinvention, one of the two governor chambers in which roughly atmosphericpressure always prevails is connected with the atmosphere only through achamber, the capacity 60 of which is so great that even rapid movementsof the control member cannot produce any substantial pressure differencein this space, in which the pressure is independent of the engine speedand roughly corresponds toatmospheric pressure. The invention is moreparticularly described with reference to the accompanying drawing, inwhich- Figure 1 is a side elevation of an internal com bustion enginewith the example of construction, and

Figure 2 is an enlarged longitudinal section through the example ofconstruction. v

The crank case a of an internal combustion engine of a motor vehiclecarries the cylinder block b with the cover c and an injection pump d, mto which fuel is fed through a pipe e.

The injection pump is driven through toothed wheels I. The sixpumpoutlets are connected through six pressure pipes a to the injectionnozzles (not shown) of the internal combustion 15 engine. On the inletside of the engine induction pipe h is flanged a branch pipe i, whichcarries a filter k for the air sucked in, and in which is rotatablymounted a throttle valve m, on the shaft of which is secured a lever n.A' pedal 0, which can be rocked by the driver. is pivotally connectedwith the lever n by means of a rod p. ,and is tensioned by a spring qwhich tends to keep the pedal 0 in the position shown, in which thethrottle valve is approximately closed.

In Figure 2, the casing l of an air pressure governor is secured to thecasing of the injection pump d. The governor casing consists of twoparts, a ring 2 flanged to the pump casing,

and a part 3 which is placed over the reduced rim of the ring. Betweenthe contact surfaces of the two parts 2 and 3 is clamped the outer partof a leather diaphragm 4, which divides the internal space of thegovernor casing into two parts 5 and 6, and the central part of which isconnected by means of two plates 1 with that end of a control rod 8which projects into the left hand chamber 5 of the governor casing, withwhich control rod the pump pistons, which are provided with obliqueedges and are not shown, can be turned for the purpose of uniform anduni-directional control of the delivery amount of the separate pumps. 'Aspring 9 accommodated in the chamber 6 abuts on one hand on the plate Iof the diaphragm 4 and on the other hand on the base of the chamber, andtends to push the control rod completely to the left, whereby it setsthe separate pumps to the full delivery amount.

In the wall of the casing part 3 of the governor is secured a shorttubular element l0, and in the wall of the induction pipe 2' is securedanother tubular element ll. Over the free ends of the two tubularelements l0 and II are placed the ends of a flexible pipe H, whichtransmits the depression prevailing in the suction pipe behind thethrottle valve on to the governor chamber C.

Into the chamber I of the governor is placed a little lubricating oil,which impregnates the leather diaphragm and keeps it pliant. A shorttubular element I3 is secured in the upper part of the governor casing.A short tubular element It is likewise fitted in the wall of the crankcasing a of the internal combustion engine. The tubular element ll opensinto the governor chamber and the tubular element ll opens into theair-filled part of the crank casing a, which is in communication withthe atmosphere by means of an air filter pipe l5 provided with an airfilter shown conventionally at lia. Over the two wide tubular elementsl3 and I4 are placed the ends of a flexible pipe It, so that thegovernor chamber 5 and the inner space of the crank case are incommunication with each other.

In the position of the throttle valve shown in Figure 1, the engine isrunning under no load and a high vacuum prevails behind the throttlevalve and in the depression chamber 6 61 the governor. -At the positionof the diaphragm which corresponds to no load, equilibrium is presentbetween the forces engaging on the membrane. In this position, thecontrol rod is well to the right, in a position in which it has set thepumps to small fuel delivery. Now if the driver opens the throttlevalvecompletely by depressing the pedal, then the pressure in the suctionpipe and in the vacuum chamber rises, and; since the pressure dropprevailing on both sides of the diaphragm suddenly decreases, the springcan displace the diaphragm rapidly to the left. Thus the air displacedfrom the chamber 5 by the diaphragm will escape rapidly through the wideflexible pipe towards the crank casing. Since the air space in the crankcasing is very large in relation to the volume of the chamber 5, thepressure in this chamber becomes balanced immediately against thepressure in thecrank casing,,which pressure corresponds approximately toatmospheric pressure.

In the converse case ota sudden falling of the pressure inthe vacuumchamber 6-, for instance,

airbymeansoianair tuations in the crank case. Since oil vapours arepresent in the crank casing, these vapours are carried over into thegovernor chamber.

These vapours keep the leather diaphragm pliant,

so that it cannot become brittle or even leaky- I declare that what Iclaim is: l. A device for governing the fuel supply to a multicylinderinjection internal combustion engine in dependence on the engine speedcomprising, in combination, a fuel injection pump having a fuel deliveryadjusting member, a governor housing. a control member therein, saidcontrol member dividing said housing into two chambers and beingoperatively connected to said adjusting member, said engine having aninduction pipe and an adjustable throttle member in said induction pipe,a pipe connecting one of said chambers with that part of the inductionpipe lying between the throttle member and the engine to reduce thepressure on one side of said control member, resilient means forresisting movement of said control member as the pressure in saidchamber is reduced, a large chamber containing clean air atsubstantially atmospheric pressure, and a pipe leading from the othergovernor chamber to said large chamber, the volume of said large chamberbeing many times larger than that 01 the other governor chamber so thatmovements of said control member cannot produce any substantial pressuredifference within said large. chamber.

2. A device according to claim '1, in which the large chamber is thecrank case of the engine.

3. A device according to claim 1, in which the large chamber is incommunication with the open filter.

